Blade sharpness testing device

Abstract

The apparatus for testing the sharpness of a blade is arranged with a tape extending between a feeder spool and a receiver spool. The apparatus applies tension to the tape, and has a carriage arranged to bring the blade into contact with a stretch of the tape. The blade progressively makes a long-ways cut in the tape and, as it does, a measuring device detects the amount of force exerted for the cut to occur to determine whether the blade is sharp. A clamp locks the stretch of tape when in a straight line for contact with the blade, and has a main opening through which the tape moves longitudinally when driven between the spools A guide is arranged to help keep the stretch of tape in the straight line and has a main opening through which the tape moves longitudinally when driven between the feeder and receiver spools.

The invention claimed is: 
     
       1. Apparatus for testing the sharpness of a cutting blade, comprising:
 tape extending between a feeder and a receiver; 
 tensioning means arranged to apply tension to the tape; 
 a carrier arranged to bring the blade and a stretch of the tape into contact such that the blade progressively makes a long-ways cut in it; 
 measuring means arranged to detect the amount of force exerted between the blade and the stretch of tape necessary for the cut to occur and, based on this, to determine whether the blade or parts of it are sufficiently sharp; 
 characterised in that the apparatus has: 
 a first clamp arranged to lock the stretch of tape when in a straight line for contact with the blade, the first clamp having a main opening through which the tape moves longitudinally when driven between the feeder and receiver, and also having a side opening arranged to enable the tape to be side-loaded into the first clamp; 
 a first guide arranged to retain a first stretch of the tape in the straight line, the first guide having a main opening through which the tape moves longitudinally when driven between the feeder and receiver and also having a side opening arranged to enable the tape to be side-loaded into the first guide; and 
 a second guide arranged to retain a second stretch of the tape in a straight line between the first and second guides such that the second stretch of tape is presented to and is engaged by a second clamp. 
 
     
     
       2. Apparatus according to  claim 1 , wherein the second guide has a main opening through which the tape moves longitudinally when driven between the feeder and receiver and also has a side opening arranged to enable the tape to be side-loaded into that guide. 
     
     
       3. Apparatus according to  claim 1 , wherein each side opening is sufficiently wide to enable the tape to pass through it side-first, but is not sufficiently wide to enable the tape to freely pass through it face first. 
     
     
       4. Apparatus according to  claim 1 , wherein the side opening of the second guide is sufficiently wide to enable the tape to be slid through it side-edge first, but is not sufficiently wide to enable the tape to pass through it face first. 
     
     
       5. Apparatus according to  claim 1 , wherein the feeder comprises a spool on which some of the tape is wound. 
     
     
       6. Apparatus according to  claim 1 , wherein the receiver comprises a spool on which some of the tape is wound. 
     
     
       7. Apparatus according to  claim 1 , wherein the feeder comprises a spool on which some of the tape is wound and the receiver comprises a spool on which some of the tape is wound. 
     
     
       8. Apparatus according to  claim 1 , wherein the tensioning means comprises a driver arranged to cause either the receiver or the feeder to pull on the tape to maintain it under tension prior to it being clamped. 
     
     
       9. Apparatus according to  claim 1 , wherein the carrier comprises a carriage arranged to travel along a downwards incline to approach the tape and make the long-ways cut. 
     
     
       10. Apparatus according to  claim 9 , comprising a downwardly inclined track along which the carriage moves. 
     
     
       11. Apparatus according to  claim 1 , wherein the first clamp comprises a lever which is able to be pivoted by spring or hand to releasably lock the tape to the clamp. 
     
     
       12. Apparatus according to  claim 1 , wherein each guide has a ledge above its side opening and the tape is face down on the ledge. 
     
     
       13. Apparatus according to  claim 1 , wherein:
 the apparatus has a force sensor attached to the first clamp such that the force sensor is adapted to detect variations of tension in the tape as the blade makes the cut, the variations being indicative of how sharp the blade is; 
 the second guide has a main opening through which the tape moves longitudinally when driven between the feeder and receiver and also has a side opening arranged to enable the tape to be side-loaded into that guide; 
 the side opening of each clamp and guide is sufficiently wide to enable the tape to be slid through it side-first, but is not sufficiently wide to enable the tape to freely pass through it face first; 
 the first clamp comprises a lever which is able to be pivoted by spring or hand to releasably lock the tape to the first clamp; 
 each guide has a ledge above its side opening and the tape is face down on the ledge; 
 the feeder comprises a spool on which some of the tape is wound and the receiver comprises a spool on which some of the tape is wound; 
 the tensioning means comprises a driver arranged to cause either the receiver or the feeder to pull on the tape to maintain it under tension prior to clamping; and 
 the carrier comprises a carriage arranged to travel along a downwards inclined track to approach the tape and make the long-ways cut. 
 
     
     
       14. Apparatus for testing the sharpness of a cutting blade, comprising:
 tape extending between a feeder and a receiver; 
 tensioning means arranged to apply tension to the tape; 
 a carrier arranged to bring the blade and a stretch of the tape into contact such that the blade progressively makes a long-ways cut in it; 
 measuring means arranged to detect the amount of force exerted between the blade and the stretch of tape necessary for the cut to occur and, based on this, to determine whether the blade or parts of it are sufficiently sharp; 
 characterised in that the apparatus has: 
 a clamp arranged to lock the stretch of tape when in a straight line for contact with the blade, the clamp having a main opening through which the tape moves longitudinally when driven between the feeder and receiver, and also having a side opening arranged to enable the tape to be side-loaded into the clamp; 
 a guide arranged to retain the stretch of tape in the straight line, the guide having a main opening through which the tape moves longitudinally when driven between the feeder and receiver and also having a side opening arranged to enable the tape to be side-loaded into the guide; and 
 a force sensor attached to the clamp, the force sensor being adapted to detect variations of tension in the tape as the blade makes the cut, the variations being indicative of how sharp the blade is.